基于高通量测序的液态奶中微生物多样性研究

目的 为探究不同液态奶样品中微生物的菌群组成和其多样性。方法 采用高通量测序技术对液态奶中细菌16S rRNA的V₃-V₄区进行测序，研究了四组液态奶样品在门水平和属水平的菌群结构。结果 四组样品中共有分类操作单元(Operational Taxonomic Unit, OTU)数目为119个，独有的OTU数分别占15.0%、6.85%、8.86%和12.35%。在门水平，厚壁菌门和变形菌门是四组液态奶的共有菌门，其中4组样品中厚壁菌门的相对丰度分别为38.9%、73.8%、20.9%、29.6%,变形菌门的相对丰度分别为46.9%、10.0%、28.0%、17.2%;在属水平，4组液态奶中的优势菌属分别是芽孢杆菌属、短波单胞菌属；芽孢杆菌属；Cloacibacterium和寡养单胞菌属；芽孢杆菌属、微杆菌属和异常球菌属。结论 四组样品在门水平的菌群组成基本相似。属水平上，液态奶中含有的不动杆菌属、芽孢杆菌属和克雷伯氏菌属属于嗜冷菌，这些菌属可以导致液态奶发生腐败变质等现象。这为今后探索液态奶中腐败菌防治措施提供重要依据。

Microbial Diversity in Liquid Milk Based on High Throughput Sequencing

Objective This study aimed to explore the composition and diversity of microbial flora in different liquid milk samples. Methods High-throughput sequencing technology was used to sequence the V3-V4 region of bacterial 16S rRNA in liquid milk, and the bacterial community structure of four groups of liquid milk samples at the phylum and genus levels was studied. Results There were 119 Operational Taxonomic Units (OTUs) in the four groups of samples,and the unique OTUs accounted for 15.0%,6.85%,8.86%,and 12.35%,respectively. At the phylum level,Firmicutes and Proteobacteria were the common phyla of the four groups of liquid milk. The relative abundances of Firmicutes in the four groups of samples were 38.9%, 73.8%,20.9%,and 29.6%,respectively. The relative abundances of Proteobacteria were 46.9%, 10.0%, 28.0%, and 17.2%,respectively. At the genus level, the dominant bacterial genera of Sample 1 were Bacillus and Brevunmdimonas, the dominant bacterial genus of Sample 2 was Bacillus, the dominant bacterial genera of Sample 3 were Cloacibacterium and Stenotrophnomonas, and the dominant bacterial genera of Sample 4 were Bacillus, Microbacterium and Deinococcus. Conclusion It can be seen from the phylum level that the composition of bacteria in the four groups of samples was basically similar. Meanwhile, at the genus level, Acinetobacter,Bacillus and Klebsiella contained in liquid milk belong to psychrophilic bacteria, which can cause spoilage and deterioration of liquid milk. This research provides an important basis for exploring the prevention and control measures of spoilage bacteria in liquid milk in the future.